Which empirical relationships are the essential successful estimator for up to 20% lbs percent clay articles; the preferred situation about sandstone reservoirs

It’s also inferred from this analysis that, the latest Shurijeh tank Creation is deposited regarding marine environment as the Th/U ratio ranged ranging from step one.8 and you will 23.dos from the gasoline generating really and between step 1.2 and you can 5.6 from the low-creating really. All of the research factors in wells realize Th/U rates below 10 proving you to, brand new depositional environment had an aquatic character. The higher Th/You ratio in the energy promoting well could be on account of much more oxidizing requirements or even increased intensity of most other radioactive nutritional elements such as for instance K-feldspar or heavy nutrition about mud size fraction. The latest intermediate Th/U proportion throughout the 2–eight on the low-generating well shown a low level from weathering and you will leaching out-of uranium, otherwise it could be inferred while the an indication of blends out of materials regarding lower and you can higher proportion environment.

The latest mix-plots research caused it to be clear the Shurijeh is not an effective brush reservoir since the collection of party studies activities just weren’t near to the origin from inside the nothing of your cross-plots revealed from the Fig. 11; these were every clustered on straight down remaining-hands corner of every cross spot. Reduced distinctions in this wells in the place of ranging from wells, suggested some clinical change like some other diagentic records ranging from wells. The content products of your gas creating well was quicker really discriminated but the showed apparently modest potassium and you can thorium with the get across patch noted A through Fig. eleven. For wells, the content circumstances for the clay entering mix-plots of land dropped from inside the a certain urban area one displayed all round systems of the clay nutrition in your neighborhood. not, specific studies of one another wells was basically moved on from the pattern. In the event, there was zero agreement into clay versions delivered because of the for every single cross-patch, however, based on the efficiency given regarding them, the latest clay mineralogy regarding formation below data might possibly be ended while the just regarding glauconite/smectite/muscovite/Illite sizes. These performance were not within the agreement thereupon of one’s XRD laboratory studies accomplished on core examples of one another wells. This new kaolinite, chlorite, and also the mixed layer clay minerals was basically together with remained unrecognized from the which petrophysical technique.

Conclusions

In this paper, all previously proposed modifications of natural gamma ray log and its spectral components data were reviewed and a new calibration equation for reliable assessment of the clay content in the Shurijeh reservoir Formation was presented. The quantitative XRD results showed a low average percentage of clay minerals for the gas producing well and moderate amounts for the non-producing well. The differences between the varying amounts of clay minerals in wells were attributed to the changes in the diagentic histories. In both wells, all the previously proposed modifications overestimated the weight percent clay indicating it is critical to calibrate petrophysically-derived weight percent clay to the laboratory data to find better estimations. The results also showed by using natural Steiber modified gamma ray values, more reliable clay contents could be obtained rather than all other previous modifications in this area. On the basis of minimum average percent relative error, the natural gamma ray and thorium curves were powerful tools to recognize the clay zones in a sandstone reservoir rather than potassium curve. In summary, the comparison of core clay contents from quantitative XRD data, estimated values using the previously proposed modifications and the empirical calibration, demonstrates that a simple nonlinear regression using the XRD data and natural gamma ray index (I_GR) allows for the quantification of clay content with the least percent relative errors, i.e., lower than 12%, which is comparable to the values of the methodological errors associated with the XRD analysis. The excellent agreement between the locally calibrated natural gamma ray index and the clay quantitative XRD data showed it was well suited to provide reliable quantitative clay content estimates. The application of the proposed approach in this paper, will significantly improve the weight percent clay estimations from the gamma ray log in the Gonbadli field. The depositional environment can be correctly recognized from the spectral gamma ray logging ratio, however the safest method of reservoir clay typing is still based on the laboratory analysis of core samples. Overall, the natural gamma ray log and its spectral components data proved to be dependable qualitative and quantitative tools to diagnose clay minerals in sub-surface formation studies. In this paper, the kod promocyjny asiandating broad scope of problem-solving capability of them was illustrated in the reservoir formation evaluation.